1. Field of Invention
The present invention relates to a gas generator suitable for a restraining device such as an airbag apparatus.
2. Description of the Related Art
In a gas generator used in a restraining device such as an airbag apparatus, various components and a gas generating agent are accommodated inside a housing forming an outer shell, and it is important to reduce the number of components and simplify the assembling process, while maintaining the high quality of the gas generator.
In the inflator shown in FIG. 1 of U.S. Pat. No. 5,582,427, a gas generating agent 30 is disposed in the lower side of a gas generating chamber 28 inside a housing, and a filter 34 is disposed in the upper side, facing an exit port 40. The housing 12 has a double-tube structure formed by an tubular outer wall 16 and an tubular inner wall 18 which are connected to a top wall 20 and a bottom wall 14, respectively.
The upper end of the filter is abutted against the top surface of the housing, and a seal 42 is arranged at the lower end to seal against gas flows. The outer circumferential edge (a leg 50) of the seal 42 is elastic. Further, in the leg 50, the distal end of the leg 50 is fitted into a groove formed in the housing wall, so that a pressing force is applied to the filter toward the top surface side, thereby sealing the upper and lower ends of the filter.
In the gas generator shown in FIG. 10 of JP-A No. 10-95303, a filter 307 is disposed in the vicinity of a gas discharge port 311 of a diffuser shell 301, and a gap 309 is formed.
The inner circumferential surface of the filter 307 is held by a plate member 332, and the lower surface thereof is held by a plate member 333.
The plate member 333 is press-fitted to the inner circumferential surface of the diffuser shell 301. The lower end of the plate member 333 is abutted against an inclined surface 331 of a closure shell 302 and holds a filter 307.
U.S. Pat. No. 7,806,954 discloses a gas generator 10 shown in FIG. 1.
Unlike the gas generators disclosed in U.S. Pat. No. 5,582,427 and JP-A No. 10-095303, a first housing portion 22 and a second housing portion 24 are joined to each other only at circumferential walls thereof.
A baffle assembly 12 is disposed inside the housing, and a filter retainer 50 is included therein. As a result, the gas generated from a gas generating composition 38 is guided by a zigzag gas discharge path to an apertures 28. An annular member 55 is welded to a booster tube 30, and the filter retainer 50 is also welded to the annular member 55.